Torpedo director



SPL 4, 1945- w. al KLEMPERER. TAL 2,384,036

ToRPEno DIRECTOR 3 Sheets-Sheet i Filed Dec. 23, 1942 muy HHH

/5 ...iil/Hllml INVENToRs ATTORNEY.

Sept 4, 1945. w. B. KLEMPERER ETAL 2,384,035

y ToRPEDo DIRECTOR l Filed Dec.. 23, 1942 5 Sheets-Sheet 2 myZ/W rrozA/Ex Sept 4,v 1945-. w. B. KLEMPERER ETAL TORPEDO DIRECTOR s sheets-sheet 3 Filed Dec. 23, 419472 INVENTORS Arwen/5y.

Patented Sept. 4, 1945 TORPEDO DIRECTOR Wolfgang B. Klemperer, West Los Angeles, and

Sydney J. Goldberg, Los Angeles, Calif., assignors to Douglas Aircraft Company, Inc., Santa4 Monica, Calif.

Application December 23, 1942, Serial No. 469,934

5 Claims.

This invention relates to a sighting device and has particular reference to a sighting device to be employed on torpedo-carrying aircraft to determine the direction in which a torpedo should be launched to hit a moving target and to determine the point in the approach of the plane to a moving target at which the torpedo should -be launched.

In the launching -from aircraft of torpedoes intended to strike moving vessels, it is necessary for the pilot of the plane to take into consideration a large number of factors including the direction of the attack approach of the plane to the target relative to the direction in which the target ship is travelling, the speed of travel of the target ship, approach of the aircraft, the calculated speed and trajectory of the torpedo during its fall through air, its loss of' speed upon striking the water, and its calculated speed in the water. By ascertaining or calculating these and other factors, the pilot determines the lead angle with which the torpedo must be launched to arrive at the collision point coincident with the arrival of the target ship at such point and the range point at which he must launch the torpedo.

All o1' these calculations and the manipulation of the plane to the range point and in the proper direction for the launching of the torpedo must be made in an extremely short space of time due to the fact that in fast moving aircraft the length of time .between the sighting of the target and the actual launching of the torpedo may be a matter of seconds only. The aeroplane comes quickly into a given firing range and leaves that given range just as quickly by reason of its great speed, therefore, it is necessary to make rapid computations and adjustments on the torpedo director and fire in a very short space of time. Surface and undersea craft, on the other hand, being relatively slow moving, permit the torpedoes to be fired at leisure bycomparison.

The torpedo director comprising the present invention has been developed especially for use on fast moving craft under conditions requiring rapid and simple calculations, and light, simple equipment.

Accordingly, it is an object of the invention to provide a means oi' rapidly determining the lead angle for firing a projectile at any given target, whether moving or stationary.

It is a further object to provide such a means that is light in weight and small so that it may be conveniently used in the limited space available in modern aircraft cockpits, and without unduly adding to the weight of the aircraft.

A further object is to provide a sighting device for use on aircraft which is readily stowable and quickly movable into position for use.

Another object is to provide a sighting device which is adaptable for use alternatively as a torpedo director or as a gun sight under emergency conditions.

A still further object of the invention lies in the combination of an open diopter sight mounted upon a mechanical interception tri-` angle.

It is another object of the invention to incorporate in a torpedo director a relatively simple range solving device asl a part of the optical system.

Other objects and advantages of the invention will be apparent from a study of the following specification, read in connection with theaccompanying drawings, wherein:

Fig. 1 is a perspective view looking at the right side of the instrument of the invention;

Fig. 2 is an end elevational view of the instrument of Fig. 1 as seen from the operators podtion;

Fig. 3 is a longitudinal vertical sectional view of the instrument;

Fig. 4 is a sectional view of an embodiment of one of the forms of the mechanical triangle portion oi' the instrument; Fig. 5 is an enlarged perspective view of the retioule incorporated in the device;

Fig. 6 is a partially schematic perspective view of o. portion of the torpedo director in what might be termed a neutra1" position;

Fig. 7 is a similar view of the device wherein` two of the legs of the triangle have been adiusted in` the steps of sighting the target;

Fig. 8 is another view similar to Figs. 6 and 7 wherein the device has been adjusted to its final position preparatory to ring; and

Fig. 9 is a diagram showing the target, the target path, the firing aircraft, sighting line and torpedo path and the geometrical relationship be tween them and the parts of the sighting device.

Referring to the drawings, Fig. 9 illustrates the geometry of a typical sighting problem, Fig. 9 having particular reference to the problem of so launching a torpedo from a moving aircraft as to cause it to strike a. moving target such as the target ship represented by the reference character TS in Fig. 9.

In Fig. 9 it has been assumed that an aircraft i carrying a torpedo is proceeding along a course represented by the line 2. This course is so directed as to intersect the target ship TS at its `then position represented by the dotted line outline of a ship bearing the reference character TS. The ship TS is assumed to be proceeding along a course represented by the line 3 at a velocity U, the course 3 making an angle 0 with a line of sight 4 extending from the aircraft I to the target ship TS.

The pilot; of the aircraft, through the use of the torpedo director disclosed herein, determines the angle by which the target ship TS must be `led in order to permit a torpedo when dropped from the aircraft to proceed along such a course `as will cause it to collide with the target ship TS. This lead angle is represented in Fig. 9 as the angle After determining the angle the pilot alters the course of the aircraft as by a veering maneuver represented by the curved line 5 to cause the aircraft to proceed along a course 6 to arelease point RP, at which point the pilot releases the torpedo.

The torpedo when released falls into the water and is propelled by its self-contained propulsion mechanism along a course 1 for a distance termed the torpedo travel range and represented by the symbol R. At the end of the torpedo travel equal to the travel range R the torpedo arrives at the collision point O and through proper determination of the lead angle the time of arrival of the torpedo at the point O is made coincident with the arrival of the target ship TS at the collision point O. In travelling from the point on.

the diagram represented by the ship outline TS to the point O, the target ship TS traverses a distance D.

By virtue of the circumstances above set forth,

` there exists an interception triangle defined by the points RP, 0.and TS. This triangle is Acharacterized by having two sides of lengths D and-R,`

respectively. and opposite angles and 0, respecl tively. From the law of sines it may be seen that D/R=sin /sin s (1) This may be rewritten as Sin ,3:(D sin 0) /R (2) From the fact that the time required for the target ship .TS to traverse the distance D is precisely equal to the time required for the torpedo to traverse the distance R, it may be stated that is thereby described and the angle is thereby defined. In this connection it is to be noted that W represents the average velocity of the torpedo as defined by the total time required for the torpedo to traverse the distance R. It will also be noted that except as W may vary with variations in R, the angle is determined by Equation 4 independently of the torpedo travel range R.

The torpedo director which isdisclosed herein operates to mechanically solve Equation 4 -by defining a mechanical interception triangle RP, O. TS in that the length of the sides of the mechanical interception triangle are proportional to the length of the respective sides of the actual interception triangle while the angles which the various sides of the mechanical interception triangle make with each other are equal to the angles which the various sides of the actual interception triangle make with each other. t

Bearing in mind the relationship between the mechanical interception triangle and the actual interception triangle, reference may again be had to Fig. 9 wherein the mechanical interception `which is directed t0 definethe sighting line 4 extending to the target ship TS at its position TS'.

In operation the sighting leg I0 is adjusted to bring the sighting line 4 to bear upon the target ship TS at its then position TS. The pilot appraises the tactical situation and chooses the torpedo travelV range which will be used in the proposed attack. The side 8 of the mechanical interception triangle is then adjusted in length to represent to a predetermined scale the magnitude of the average torpedo velocity W corre spending to the chosen range R. The side 9 is turned to parallelism with the estimated direction of the course 3 pursued by the target ship thus defined between the sides 9 and I0 the angle 0.

The velocity U of the target ship is estimated or determined from known facts relating to the particular nationality and type of ship comprising the target ship TS and the side 9 is adjusted in length to represent the determined velocity U of the target ship TS to the same predetermined scale as was used in adjusting the length of the side 8. When these adjustments are made, the mechanical interception triangle 1s fixed and the angle between the sides 8 and I0 comprises the angle ,c which is' the correct angular amount by which'the target must be led in order to cause a. collision between the released torpedo and the target ship.

The entire mechanical triangle 8, 9, I0 is then pivoted about a point II in such direction and by such amount as is required to bring the side 8 into parallelism with the then course of the aircraft. I. 'Ihis disposes the mechanical interception triangle in the position illustrated by dotted lines in Fig. 9 and extends the sighting line defined by the sighting leg I0 in the direction indicated by the dotted arrow I2. By the veering maneuver 5 the pilot of the aircraft so changes the course of the aircraft as to bring the sight ing line I2 to again bear on the target ship TS.

Having completed this maneuver, the pilot then proceeds along the course 6, 1 which is so chosen as to maintain the sighting line I2 on the target ship TS as is represented, for example, by thel line I2a in Fig. 9. Asthe aircraft proceeds along the course 6 it approaches a release point RP which is chosen to be distant from the collision point O a .distance equal to the chosen torpedo travel range R. Mechanism to bedescribed hereinafter indicates arrival at the point RP and the torpedo is released and the desired collision between the torpedo and the target ship ensues.

Fig. 9 represents an approximate diagram of the geometry involved in the launching of a torpedo and differs from the actual conditions encountered in practice in that certain of the courses, such as the course 6, are shown as a straight line, whereas, in fact, Athe course 6 is slightly curved to comprise a homing path. The approximate representation in Fig. 9 is, however, correct for all practical purposes since it may' be readily shown that the error introduced by ignoring the curvature of the line and treating it as a straight line is of such small magnitude as to be substantially negligible, and since, further, the direction of the side 9 may be adjusted from time to time as may be required to maintainl the same in approximate parallelism with the course 3 being pursued by the target ship TS, this latter adjustment serving to recorrect the angle to compensate for any differences that may result from the course of the aircraft being curved rather than straight.

With reference now to Figs. 1 and 2 the torpedo director comprising the invention includes a vertical tubular member I3 carrying at its upper end a horizontally extending channel-shaped leg or sighting member I4 and at its lower end an elbow-shaped light and reticle housing I5. 'I'hese members are fastened together by a plurality of bolts I6 so that they may be readily disassembled. The director is placed in the aircraft or other vehicle upon which it is to be used, in a position such that the leg I4 may parallel the longitudinal center-line of the aircraft with the leg I4 extending forwards from the tubular member I3 in the direction of the arrow I4a in Fig. l.

vAs stated above the leg I4 is of channel shape with the curved-up `sides thereof tapering from a maximum height at the rear to a minimum height at the front. The bottom portion of the channel is cut out at the rear so as not to overlie the tubular member I3 and to permit the light from the elbow section I to exit therefrom. The bottom portion`is similarly cut out at the front so as not to unduly interfere with the pilots downward vision as he sights through the device. 'Ihe leg I 4 actually serves as one leg of the mechanical I5 and bearing against the reticule. Any movement of the reticule by the screw 42 is resisted by a leaf spring 44 secured to one of the upstanding portions 40 of the annular member 33 and this spring is of suiilcient strength to move the reticule toward the screw 42 as the latter is backed oiI. The spring also serves to hold the reticule securely vagainst vibration. Rotational adjustment of the reticule about its center is accomplished by a pair of screws 46, one threaded throughout each side of the elbow I5 and bearing against a pin 4l subtending from the annular member 38.

The reticule is provided with two stadia lines 5l, one at either end of the horizontal cross hair, and this length is further divided by a plurality of short vertical lines to further assist range de, termination. The stadia lines 50 are preferably so spaced that they appear ten percent of interception triangle; that is, it is the sighting leg and is provided with a sighting line in the form of a groove I8 extending longitudinally along the center and painted white so as to be readily visible in event of failure of the artificial illumination. As a matter of fact this line is used for sighting only 'in just such an emergency since normal sighting is by way of a reticule pattern reilected upon an angularly positioned lighttransmitting .-eflector or mirror 20 which may be of approximately twenty-five (25%) percent reflecting quality. f

The mirror section is covered by a cap 22 fastened at 24 to the aft end of the channel-shaped leg I4, and this cap mounts a hinged filter 26 of light polarizing material which may be snapped down to close oil the forward end of the capped portion to eliminate glare or blinding when the sight is being used against sunlight reflected from the water. A small lever 28 xed to the filter.

permits it to be quickly moved to the desired position.

The elbow-shaped housing I5 at the lower end of the vertical tubular member I3 is adapted to receive a light bulb 30 as best shown in Fig. 3.

the sighted range apart, each being approximately five percent of the sighted range from the centerline.

The reticule appears to the eye oi' the pilot as a luminous reflection on the mirror 20 as shown in Fig. 2, being projected thereon by the light 30 shining through the reticule in the elbow and a lens 52 mounted in the upper portion of the vertical housing I3 a distance above the reticule equal to its focal length. The optics of the refiector sight are so collimated that movement of the eye across the field of the reflector will cause no substantial error. The eye may be positioned at any desired distance from the mirror 20 and in each chosen position the luminous reticule lines appear to be projected upon the object sighted so that the object and the cross hairs are simultaneously in focus and appear to be substantially equally distant from the observer.

The entire director is adapted to pivot on a king pin 54 interconnecting two forwardly projecting ears 56 and 58 whichare an integral pmt of the vertical tubular member I3, thus permitting the sighting line defined by the sighting member I4 and the optical system just described'to be moved to any desired angular position. Between the ears 56 and 58 the king pin mounts a horizontally extending bracket 6I) which is bolted at its opposite end to a short length of square tube 82 or the like. The square f tube 62 is slidable overl a slightly smaller tube 64 partially shown by dotted lines in Fig. 1, the

. latter extending the full or a substantial part of The bulb may be removed readily for replacement by merely unscrewing a knurled collar 32 which releases the bulb socket 34. When the bulb is properly in place and lighted, it illuminates a reticule 36 mounted in the elbow at the upper end thereof. The reticule is shown in detail in Fig, 5. An annular member 38 mounted within a recess 39 provided in the elbow I5 supports the reticule and is provided with upstand.

ing portions 40 serving as guides to hold the reticule in its proper position. The reticule may be adjusted relative to the member 38 by means of a long screw 42 threaded through the elbow the Width F of the aeroplane cockpit so as to permit the director to be moved to one side or the other for stowage and to be adjusted to the pilots convenience for sighting. A braking device 66 incorporating a spring-loaded cam action is provided to arrest the movement of the di` rector along the tube 84 and securely hold it in any desired position along the tubes length As stated, the entire -director is adapted to pivot on the king pin relative to its mounting tube, but it also may be locked in a position normal to the tube 84 so that the sighting leg I4 is parallel to the longitudinal centerline of the aircraft. This locking action is accomplished by a bifurcated spring arm 61 secured to the bracket 60, the upper division of the arm 81 being bent over to form a lug 88. The lug rides along the periphery of a flange 'I0 forming an integral part oi' a bearing 12 in which the upper portion of the king pin 54 rotates. The bearing is locked to the upper ear B6 by a bolt 14 so that it must rotate therewith whenever the sighting member I4 is angularly moved.

The flange has a single notch 16 cut therein which is adapted to receive the lug 68 of the bi-l furcated spring arm 61, the spring forcing the Referring particularly to Fig. 3, it will be noted that during the time of making the various adjustments and settings of the torpedo arm 96 and lug into the notch as soon as they come into f alignment. The parts are so adjusted that as long as the lug and notch are in engagement, the sighting leg |4 of the director is held parallel to the longitudinal centerline of the aircraft and normal to the transverse mounting tube 84.

The lower division of the bifurcated spring arm 61 is also bent over to form a lug 86 which functions in a manner similar to the lug 68, on the upper division. In other words, it is adapted to engage a notch 88 in the periphery of a flanged member 86 having a squared center fitting over a squared portion 92 of the king pin 54. By reason of the squared mating parts the flanged member 88 is forced to rotate with the king pin whenever the latter is turned therefore the notch 88 will assume different positions upon rotation of the king pin.

The portion of the king pin which extends above ear 56 ,is serrated at 94 and fits tightly into a bore in the rear end of a second arm 96 of the mechanical interception triangle, hereinarm 61 is such that either division of the bifurcation may be moved into or out of engagement with the flange notches without aecting lthe position of the other division.

will be later described and this movement is accomplished by the rotation of a knob |36. The knob is provided with an indexing pointer `I38 and is adapted to rotate a shaft |48 upon which a cam |42 is fixed. The cam lies behind the upper and lower divisions of the bifurcated spring arm and is adapted by its eccentricity to contact one or the other or both or neither of the spring arm divisions so that either, both or neither of the lugs 68 and 86 will be in a position to engage their respective notches in the flanges 18 and 80.

When both notches are in vertical alignment, all parts of the director being in the neutral position, rotation of the knob index |38 to the aft position will move the cam from contact with both spring arm divisions and permit both ofthe divisions thereof to move into notch engaging positions and lock all parts of the director against movement. Rotation of the index to an upward pointing position will cause the cam |42 to raise the lower division lug to a notch free position releasing the torpedo arm 86 but holding the sighting leg i4 in alignment with the axis of the aircraft. Further rotation of the index to a forward pointing position will cause the cam to raise both lugs into a notch free position in which both the torpedo arm 96 and the sighting leg I4 may be moved. When the index is pointed dow'nward, the upper lug is raised and the lower lug is in notch engaging position to hold the torpedo arm 98 in alignment withl the axis of the aircraft. If either notch is not in alignment with its respective lug and the lug is released by the cam, it will merely ride along the flange and snap into the notch when they become aligned.

In setting the di. rector these divisions are alternately moved as the third arm |02, these arms should bereadily movable relative to each other and to the body of the director which defines the sighting line or third side of the triangle when force is applied to them to set them at the correct angles and yet they should be so connected together as to remain in the positions to which they are set while the various adjustments and settings are being made.

This may be readily accomplished by employlng the king pin construction illustrated in Fig. 3 in which the upper bearing 12 (which carries the upper flange 10) is provided with an inwardly and downwardly tapering bore for frictionally receiving a tapered enlargement of the king pin 54. Also the under surface of the bearing member 12 is provided with an upwardly and inwardly extending taper to receive and frictionally en- Hage a bearing sleeve 60a.

The lower flange member 80 is likewise provided with an upwardly and inwardly tapering upper surface adapted to engage a corresponding surface on the bearing sleeve 60a and is provided at its under surface with 'an inwardly tapering bore adapted to engage a correspondingly shaped surface on a bearing nut 58a which is adjustably threaded into the lower ear 58. Thus by tightening the nut 58a all of the parts of the bearing assembly are drawn into accurate alignment with each other and any desired amount of friction between the flange member 80 and the body of the sighting device may be imparted by the upward thrust of the nut against the flange member 98. which thrust will be imparted through the sleeve 60a to the upper or fixed bearing member 12.

Likewise the king pin 54 may be accurately centered in the bearing member 12 by separately drawing the king pin downwardly relative to the bearing member as by a second locking nut 54a threaded upon the lower end of the king pin 54 and bearing against a spring 56h interposed between the nut 54a and a shoulder on the counterbore of the main lock nut 68a.

With reference to the attachment of the bracket 60 to the transverse tube 62, it is so arranged that the front portion of the director may be lowered approximately seven degrees by manipulation of a lever 18 mounted upon a cam shaft 80, the cam forcing the director to tilt upon rotation of the shaft. The director tilts about a horizontal axis coaxial with a bolt 82 extending through two lugs 84, which are a part of the short square tube 62, and connecting the horizontal bracket 68 thereto. Forced tilting of the director relative to the square tube is resisted firmly at all times and .will return to its normal position immediately upon being relieved by robearing |00.

tation of the cammed shaft 80. The tilting feature is provided for the purpose of allowing greater downward vision when needed as the aircraft may be nosed up to be slowed down during thetorpedo attack approach. The degree of tilt may be varied to suit the requirements of different aircraft designs.

The end of 'the torpedo arm 96' opposite to the king pin 54 is provided with a bore 98 having one side thereof countersunk to receive a tapered One end of the bearing protrudes below the arm 96 and is threaded to receive a locking knob |0|. The other end of the bearing protrudes above the arm 86 and is serrated so as to iit tightly into a bore in the end of a third arm |02 of the mechanical interception triangle. This arm represents the velocity vector of the target in water and is consequently called the target arm. In the adjustment of the triangle the torpedo and target arm pivot about the bearing and. when the proper adjustment is had the locking knob |0| is tightened to hold the two arms against further relative movement,

The length of the target arm is adjustable to correspondence with the velocity of the target and so is provided with an inset rack' |04 which is adapted to mesh with a pinion gear |06 disposed in a small housing |00. the gear |06 being provided for the purpose of moving the arm longitudinally relative to the housing |08 in response to rotation of a knob ||0. The housing |08 may carry indexing pointers I I2 for use in conjunction with suitable calibrations on the target arm |02 and knob ||0 for determining the settings of both the target arm and the pinion knob.

'I'he housing |08 is pivoted to a plate I lI4 which is adapted to slide on tracks ||6 provided on each side of the sighting leg |4 and by such sliding motion the eliective length of the sighting leg may be varied to suit different conditions. Thus it maybe seen that with the sighting leg adjustable in eii'ective length as just described and the target leg adjustable in effective length by operating the rack and pinion, the entire triangle may be adjusted at will both as to the length of the respective legs and their included angles.

It will be noted in the embodiment of the torpedo director shown in Figs. 1 and 3 that thetorpedo leg 86 is not adjustable. In that embodiment the leg is of an eiective length corresponding to a predetermined torpedo speed, which speed is that averaged Iby the torpedo throughout a preselected standard travel range when dropped from an aircraft at a standard altitude and travelling at a standard speed. This is in accordance with one of the conventional torpedoing practices. However, it is conceivable that conditions may arise under which one might desire to release the torpedo at a. different height and speed. In such an instance an inversely proportional correction may Ibe applied to the adjustable length of the target arm, or else the torpedo speed leg would have to be of a length corresponding to the different average torpedo travel speed. For that reason an adjustable torpedo leg 96 has been developed and is shown in detail in Fig. 4.

The two terminals of the adjustable leg are substantially identical with the corresponding terminals of the fixed length leg 96. I'hat is, one end is provided with a tapered bore II8 for pivotal connection to the target leg |02 and the other end has a bore |20 adapted to t tightly over the serrated top portion of the king pin 54.

.The inner portion `|22 of the adjustable leg carries a rack |24 fastened thereto by screws |26. It is this portion that extends from and retracts into the outer portion |26 of the leg. 'I'he outer portion carries a small pinion |30 in mesh with the rack teeth and is rotated by a knob |32 to move the rack translationally in either extension or retraction.

An intermediate member |34 lies between the inner and outer portions of the leg and is adapted to improve the rigidity thereof as it approaches its maximum extension. To enhance quick adjustment of the leg, the pinion knob l|32 should be calibrated in knots 'corresponding to average torpedo speeds at diilerent leg lengths, or it may be calibrated in a manner to give'diflerent combinations of launching heights and speeds with the length of the leg automatically being set,

to the proper torpedo speed for any given launching height and speed condition.

It will be understood that the instrument with fixed torpedo arm length is readily adaptable to correction for any deliberate deviation vfrom the standard torpedo travel range. As each diiierent torpedo travel range would correspond to a slightly diierent average torpedo speed, a proportional correction of the scale in which the mechanical triangle represents the interception triangle will take care of the variation in the torpedo travel range. All that is necessary is to apply an inversely proportiona1 correction to the estimated target speed U. Such corrections may be derived from charts previously prepared or other suitable calculating aids.

The mod e of operation of the apparatus just described may perhaps be best understood by having reference to Figs. 6, 7 and 8 wherein the moving parts of the director are shown in perspective and divorced from the remainder of the apparatus. As before stated, the first operation which is performed by the pilot of the aircraft in approaching the target ship TS is to so position the sighting leg |4 as to extend the sighting line 4 defined thereby in `a direction to bear upon the target ship TS. This may be conveniently accomplished in the manner illustrated in Fig. 6 by locking the director in the neutral position; that is, with the lug 68 engaging thenotch 16 and with the lug 86 engaging the notch 88.

This is accomplished by turning the knob |36 to .an aft position of the indexing pointer |38. When this condition obtains, the torpedo arm 96' and the sighting leg I4. (represented by the black arrow |4' in Fig. 6) are both aligned with the axis of the aircraft. The sighting line 4 defined. by the sighting leg |4 may then be maintained on the target ship TS by merely so lguiding the aircraft that the forward extension of its course will intersect the target ship TS. When the adjustable torpedo arm 06 is employed, the `pilot then appraises the tactical situation 'and chooses the torpedo travel range best calculatedto provide for a successful attack upon the target ship. By means of the knob |32 the length of the torpedo arm 96 is then adjusted to correspondence with the average torpedo velocity which corresponds to the chosen range. If the director is equipped with the xed torpedo arm 96, this operation is, of course, omitted and the torpedo travel range is preferably chosen as closely as possible to that corresponding to the average torpedo velocity represented by the length of the ilxed arm 96.

The pilot of the aircraft then turns the target arm |02 to parallelism with the course 3 of the target ship and through use of the knob ||0 adjusts the length of the target arm |02 to represent the determined velocity of the target ship. This operation must of necessity result in a rotation of the torpedo arm 96 and so must be preceded by the turning of the knob |36 to an upward pointing position such as illustrated in Fig. 6 to remove the lug 86 from the notch 68 and release the king 4 pin 54 to permit the arm 96 to be rotated. The sighting leg |4 is in the meantime held aligned with the axis of the aircraft through engagement c of the lug 60 with the notch 16.

target arm |02 and torpedo arm 96 immovably relative to each other and this operation ixes the mechanical interception triangle. The result of this operation is represented by the new relative disposition of partsjwhich is shown in Fig. 7.

Having flxedthe mechanical interception triangle, the pilot must next execute the veering maneuver 5 and as a. prelude to this, the position o f the mechanical interception triangle is shifted from that illustrated by the solid lines in Fig. 9 to that` illustrated by the dotted lines in 1 the lug 86 is released to resiliently bear against the periphery of the flanged member 80. The notch 88 will be brought into a position registering with the lug 86 through rotation of the iianged member 90 by movement of the mechanical interv ception triangle and the king pin 54 the amount required to bring the torpedo arm 98 into alignment with the axis of the aircraft.

Whenthis condition obtains the lug 86 will spring into the notch 88 by virtue of the resilient character of the bifurcated member 61 and will thus serve to hold the torpedo-arm 96 in the desired aligned position. The veering maneuver 5 is then effected to bring the sighting line 4 to again bear upon the target ship TS, the relative positions of the parts when this condition obtains being illustrated in Fig. 8. tablished the desired torpedo course and having started the aircraft along that course, the pilot proceeds to the release point RP and releases the torpedo.

The foregoing description has been carried forwardon the assumption that the pilot of the aircraft will in some way be aware of his arrival at the release point RP. As hereinbefore noted, the shape of the interception triangle is dependent upon the chosen torpedo travel range R only to the extent that the average velocity W of the torpedo is dependent upon the distance the torpedo travels. For relatively long ranges and low launching velocities the reiiect of a change in torpedo travel range from the average velocity of the torpedo is relatively small so that an accurate determination of the location of the release point RP is not required. However, for ranges differing widely from that to which the length of the torpedo arm 88 or 86' corresponds or for relatively high launching velocities, the requirement for accurately determining the location of the release point RP becomes more stringent,

The torpedo director disclosed herein is accordingly provided withrranging equipment which will permit the location of the release point RP to beaccurately determined in terms of the sighting range; that is, the distance from the release 'point RP to the position of the target ship TS at the time the torpedo is released. This mechanism includes the calculating mechanism comprising a rotatable member |46, a sliding member |41 Iand an indicating scale |48; The rotatable member |46 comprises a sleeve surrounding the vertical tubular portion i3 of the director and is equipped with a gear segment |49 which Having thus esmeshes with a second gear segment |50 secured to the'king pin 54 so as to be rotated by pivotal movement of the torpedo arm 96.

Upon the exterior surface of the member |46 is engraved a family vof 0 curves |5|, these curves being provided with suitable reference indicia |52 and representing various values of the target approach angle 0.

To permit the pilot to measure the target approach angle 0, the housing |08 is provided with a protractor |53 which coacts with a suitable index carried by the sliding plate I|4 to indicate directly on the protractor |53 Ithe magnitude of the target approach angle 0. The sliding member |41 is provided with graduations |54 representative of the chosen torpedo travel range. In operation Athe sliding member` |41 is moved vertically to a position such that the R scale graduations |54 corresponding to the chosen travel range lie opposite that one of the family of curves |5| which corresponds -to the target ap proach angle 0 indicated on the protractor |53.

'I'he sliding member |41 is also provided with a second set of graduations |55 representative of the known length of the target ship TS. This length is considered to be known by the pilot of the airchaft since he will be able to determine from its appearance the nationality and type of the target shipand from these facts the pilot will know or have at his disposal the pertinent data relative to the target ship TS including i-ts actual length. The pilot then observes the position relative to the fixed indicating scale I 48 of that one of the graduations |55 on the L scale which represents the known length of the target ship TS:

The scale 48 is provided with 'graduations |56 so that the pilot may read on the S scale |48 opposite the graduatlons |55 representing ,the length of the target ship TS 'the number of stadia divisions of the reticule through which the apparent observed length of the target ship TS should extend when the aircraft has arrived at the release point RP. The pilot then proceeds along the course 6 until the apparent size of the target ship has expanded to just exactly subtend the number of stadia divisions indicated on the scale |48 and by noting the expansion of the apparent size of the target ship to this extent, the pilot is thereby apprised of his arrival at the release point RP.

From the foregoing it will be observed that the torpedo director disclosed herein provides for the ready and accurate determination of the lead angle and provides also a sighting means whereby the course of the aircraft may be so maintained that the torpedo when released will proceed along a course leading to target ship TS by the amount required to effect collision between the torpedo and the target ship.

It will also be observed thatthere is provided a ranging mechanism by which the pilot may be readily apprised of his arrival at a release point corresponding to a torpedo travel range previously chosen with due regard to the tactical situation involved in the attack.

It will also be noted that the'device described is so arranged that the director may be moved to one side out of the way of the pilot when not in use and so that it may be moved to any desired operative position most convenient and accessible to the pilot when the device is being employed to direct a torpedo.

Further, the fact that the instrument is readily slidable along its mounting tube 64 allows the ily susceptible to use as an emergency gun sight by merely locking the sighting leg Il in a position aligned with the axis of the aircraft as by engaging the lug 8B with the notch 1l through turning of the knob |36 to an upwardly pointing position of the index In. By this means the aircraft may be so guided as to bring the line of fire of fixed guns mounted on the aircraft to bear upon any target upon which the sighting line l is lbrought to bear.

It may be found more convenient to mount the instrument in a position inverted from that shown in the drawings, and it will be apparent that vsuch inverted mounting will not in any way affect the operation of the instrument to perform all of the functions described herein.

While there has been shown and described the preferred embodiment of the invention, it is not desired that the same be limited to any of the details of construction shown or described herein, except as defined in the appendedy claims.

What is claimed as new is:

l. In a torpedo director for use on an aircraft carrying a torpedo, the combination of: an adiustable mechanical triangle for reproducing on a reduced scale the velocityvector triangle denning the relative motions of said aircraft, said torpedo, and the target intended to be hit by said torpedo, said triangle including a sighting arm defining a sighting line and a torpedo arm representing the velocity vector of said torpedo relative to the water into which it is to be launched; means mounting said triangle for pivotal movement as a unit to a position disposing saidtorpedo arm parallel to the motion of said aircraft; latching means carried by said aircraft for selectively engaging said sighting arm and said torpedo arm and holding the same against movement and in positions respectivelyr parallel to the direction direction of motion of said aircraft; and a control member coacting with said latching means, said control member being movable to four unique positions, in the rst of which said latching means is held out of engagement with both of said arms, 4in the second of which said latching means is engaged withJboth of said arms, in the third of which said latching means is engaged with one` vonly of said arms, and in the fourth of which said latching means lis engaged only with the other of said arms.

3. A projectile director for use on a mobile vehicle comprising a mechanical triangle for reproducing ona reduced scale the velocity vector triangle representing the respective magnitudes and directions of the speed of the projectile relative to the earth, the speed of the vehicle relative to the target to be torpedoed, and the speed of the target relative to the earth, means mounting said mechanical triangle on the vehicle for pivotal movement about a center coincident with the vertex formed between the sides of the'triarigle representing respectively the projectile direction and the direction of the vehicle, means for latching said director in a position about said pivot means aligning said vehicle direction side in a position ,extending fore and aft of said vehicle, means of motion of said aircraft; and a movable control member coacting with said latching means and operable upon movement to one position to engage said latching means only with said sighting arm and operable upon movement to another position to engage said latching means only with said torpedo arm.

movable relative to said mounting means land to said first named latching means in correspondence with the angular deviation of said projectile direction side of said triangle to define a second latch position disposed relative to the fore and aft line of the vehicle at the same angle as the angle between said two sides of said triangle, and

detent means engageable with the ilrst of said latch means when said vehicle direction side of said triangle is aligned with the fore and aft line of the vehicle and engageable with the other of said latch means when the-projectile direction side of said triangle is aligned with the fore and aft line of said vehicle.

4. A projectile director for use on a mobile vehicle comprising a mechanical triangle for reproducing on a reduced scale the velocity vector triangle representing therespective magnitudes and directions of the speed of the projectile relative to the earth, the speed of the vehicle relative to the target to be torpedoed, and the speed of the target relative to the earth, and means mounting said mechanical triangle on sa/id vehicle for lateral translatory movement at right angles to the fore and ai't line of the vehicle and for lateral pivotal movement about a substan- 2. In a torpedo director for use on an aircraft y,

carrying a torpedo, the combination of i an adjustable mechanical triangle for reproducing on a reduced scale the velocity vector triangle defining the relative motions of said aircraft, said torpedo, and the target intended to be hit by said torpedo, said triangle including a sighting arm defining a sighting line and a torpedo arm representing the velocity vector of said torpedo relative to the water into which it is to be launched; means mounting said triangle for pivotal movement as a unit to a position disposing said torpedo arm parallel to the motion of said airpraft; latching means carried by said aircraft for selectively engaging said sighting arm and safid torpedo arm and holding the same against movement and in positions respectively parallel to the tially vertical axis passing'through'the vertex formed between the sides of the triangle representing respectively the speed of the projectile and the speedof the vehicle, whereby either of said sides may bealigned with the fore and aft line of the vehicle and may be shifted into the line of vision of the operator of the projectile director in either of said angular positions.

5. In an aircraft, a device for so launching a torpedo as to cause it to strike a target moving in a given direction relative to said aircraft and at a given speed, comprising: a sighting arm for defining a sighting line; means mounting said arm on said aircraft for movement to a position directing said sighting line toward said target; a second arm for representing the speed of -said target; a third arm havingfa length representing the average speed of said torpedo, said third arm being pivotally connected at opposite ends to said sighting arm and said second arm; means for adjusting the effective length of said second arm to correspondence with said` given target speed.

` means for adjusting the angular relation of said sighting arm and said second arm in accordance with the direction of motion of said target; pivotal means about which the position of said triangle may be adjusted as a whole relative to said Vvehicle in an amount sufficient to bring said third arm into a position paralleling the course of said aircraft, said pivotal means interconnecting said third arm and said sighting arm; and means for imparting -friction between said vehicle, said `.sighting arm and said third arm, whereby said 

